[PATCH 5/8] ntoskrnl.exe: Implement ExAcquireSharedWaitForExclusive().
Zebediah Figura
z.figura12 at gmail.com
Mon Apr 8 16:57:52 CDT 2019
Signed-off-by: Zebediah Figura <z.figura12 at gmail.com>
---
dlls/ntoskrnl.exe/ntoskrnl.exe.spec | 2 +-
dlls/ntoskrnl.exe/sync.c | 62 +++++++++++++++++++++++++++++
include/ddk/wdm.h | 1 +
3 files changed, 64 insertions(+), 1 deletion(-)
diff --git a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
index 347febb63f..ee26d8b6e2 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
+++ b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
@@ -123,7 +123,7 @@
@ stdcall ExAcquireResourceExclusiveLite(ptr long)
@ stdcall ExAcquireResourceSharedLite(ptr long)
@ stdcall ExAcquireSharedStarveExclusive(ptr long)
-@ stub ExAcquireSharedWaitForExclusive
+@ stdcall ExAcquireSharedWaitForExclusive(ptr long)
@ stub ExAllocateFromPagedLookasideList
@ stdcall ExAllocatePool(long long)
@ stdcall ExAllocatePoolWithQuota(long long)
diff --git a/dlls/ntoskrnl.exe/sync.c b/dlls/ntoskrnl.exe/sync.c
index 2b362efc82..e89fddcbba 100644
--- a/dlls/ntoskrnl.exe/sync.c
+++ b/dlls/ntoskrnl.exe/sync.c
@@ -944,3 +944,65 @@ BOOLEAN WINAPI ExAcquireSharedStarveExclusive( ERESOURCE *resource, BOOLEAN wait
return TRUE;
}
+
+/***********************************************************************
+ * ExAcquireSharedWaitForExclusive (NTOSKRNL.EXE.@)
+ */
+BOOLEAN WINAPI ExAcquireSharedWaitForExclusive( ERESOURCE *resource, BOOLEAN wait )
+{
+ OWNER_ENTRY *entry;
+ KIRQL irql;
+
+ TRACE("resource %p, wait %u.\n", resource, wait);
+
+ KeAcquireSpinLock( &resource->SpinLock, &irql );
+
+ entry = resource_get_shared_entry( resource, (ERESOURCE_THREAD)KeGetCurrentThread() );
+
+ if (resource->Flag & ResourceOwnedExclusive)
+ {
+ if (resource->OwnerEntry.OwnerThread == (ERESOURCE_THREAD)KeGetCurrentThread())
+ {
+ /* We own the resource exclusively, so increase recursion. */
+ resource->ActiveEntries++;
+ KeReleaseSpinLock( &resource->SpinLock, irql );
+ return TRUE;
+ }
+ }
+ /* We may only grab the resource if there are no exclusive waiters, even if
+ * we already own it shared. */
+ else if (!resource->NumberOfExclusiveWaiters)
+ {
+ entry->OwnerCount++;
+ resource->ActiveEntries++;
+ KeReleaseSpinLock( &resource->SpinLock, irql );
+ return TRUE;
+ }
+
+ if (!wait)
+ {
+ KeReleaseSpinLock( &resource->SpinLock, irql );
+ return FALSE;
+ }
+
+ if (!resource->SharedWaiters)
+ {
+ resource->SharedWaiters = heap_alloc( sizeof(*resource->SharedWaiters) );
+ KeInitializeSemaphore( resource->SharedWaiters, 0, INT_MAX );
+ }
+ resource->NumberOfSharedWaiters++;
+
+ KeReleaseSpinLock( &resource->SpinLock, irql );
+
+ KeWaitForSingleObject( resource->SharedWaiters, Executive, KernelMode, FALSE, NULL );
+
+ KeAcquireSpinLock( &resource->SpinLock, &irql );
+
+ entry->OwnerCount++;
+ resource->ActiveEntries++;
+ resource->NumberOfSharedWaiters--;
+
+ KeReleaseSpinLock( &resource->SpinLock, irql );
+
+ return TRUE;
+}
diff --git a/include/ddk/wdm.h b/include/ddk/wdm.h
index 8023fda64e..4609790a66 100644
--- a/include/ddk/wdm.h
+++ b/include/ddk/wdm.h
@@ -1515,6 +1515,7 @@ void WINAPI ExAcquireFastMutexUnsafe(PFAST_MUTEX);
BOOLEAN WINAPI ExAcquireResourceExclusiveLite(ERESOURCE*,BOOLEAN);
BOOLEAN WINAPI ExAcquireResourceSharedLite(ERESOURCE*,BOOLEAN);
BOOLEAN WINAPI ExAcquireSharedStarveExclusive(ERESOURCE*,BOOLEAN);
+BOOLEAN WINAPI ExAcquireSharedWaitForExclusive(ERESOURCE*,BOOLEAN);
PVOID WINAPI ExAllocatePool(POOL_TYPE,SIZE_T);
PVOID WINAPI ExAllocatePoolWithQuota(POOL_TYPE,SIZE_T);
PVOID WINAPI ExAllocatePoolWithTag(POOL_TYPE,SIZE_T,ULONG);
--
2.21.0
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